File: src\Framework\System\Windows\CornerRadiusConverter.cs
Project: wpf\PresentationFramework.csproj (PresentationFramework)
//---------------------------------------------------------------------------
//
// Copyright (C) Microsoft Corporation.  All rights reserved.
// 
// File: CornerRadiusConverter.cs
//
// Description: Contains the CornerRadiusConverter: TypeConverter for the CornerRadiusclass.
//
// History:  
//  07/19/2004 : t-jaredg - Created
//
//---------------------------------------------------------------------------
 
using System;
using System.ComponentModel;
using System.ComponentModel.Design.Serialization;
using System.Globalization;
using System.Reflection;
using System.Text;
using System.Windows;
using System.Security;
using MS.Internal;
using MS.Utility;
 
#pragma warning disable 1634, 1691  // suppressing PreSharp warnings
 
namespace System.Windows
{
    /// <summary>
    /// CornerRadiusConverter - Converter class for converting instances of other types to and from CornerRadius instances.
    /// </summary> 
    public class CornerRadiusConverter : TypeConverter
    {
        #region Public Methods
 
        /// <summary>
        /// CanConvertFrom - Returns whether or not this class can convert from a given type.
        /// </summary>
        /// <returns>
        /// bool - True if thie converter can convert from the provided type, false if not.
        /// </returns>
        /// <param name="typeDescriptorContext"> The ITypeDescriptorContext for this call. </param>
        /// <param name="sourceType"> The Type being queried for support. </param>
        public override bool CanConvertFrom(ITypeDescriptorContext typeDescriptorContext, Type sourceType)
        {
            // We can only handle strings, integral and floating types
            TypeCode tc = Type.GetTypeCode(sourceType);
            switch (tc)
            {
                case TypeCode.String:
                case TypeCode.Decimal:
                case TypeCode.Single:
                case TypeCode.Double:
                case TypeCode.Int16:
                case TypeCode.Int32:
                case TypeCode.Int64:
                case TypeCode.UInt16:
                case TypeCode.UInt32:
                case TypeCode.UInt64:
                    return true;
 
                default:
                    return false;
            }
        }
 
        /// <summary>
        /// CanConvertTo - Returns whether or not this class can convert to a given type.
        /// </summary>
        /// <returns>
        /// bool - True if this converter can convert to the provided type, false if not.
        /// </returns>
        /// <param name="typeDescriptorContext"> The ITypeDescriptorContext for this call. </param>
        /// <param name="destinationType"> The Type being queried for support. </param>
        public override bool CanConvertTo(ITypeDescriptorContext typeDescriptorContext, Type destinationType)
        {
            // We can convert to an InstanceDescriptor or to a string.
            if (    destinationType == typeof(InstanceDescriptor) 
                ||  destinationType == typeof(string))
            {
                return true;
            }
            else
            {
                return false;
            }
        }
 
        /// <summary>
        /// ConvertFrom - Attempt to convert to a CornerRadius from the given object
        /// </summary>
        /// <returns>
        /// The CornerRadius which was constructed.
        /// </returns>
        /// <exception cref="ArgumentNullException">
        /// An ArgumentNullException is thrown if the example object is null.
        /// </exception>
        /// <exception cref="ArgumentException">
        /// An ArgumentException is thrown if the example object is not null and is not a valid type
        /// which can be converted to a CornerRadius.
        /// </exception>
        /// <param name="typeDescriptorContext"> The ITypeDescriptorContext for this call. </param>
        /// <param name="cultureInfo"> The CultureInfo which is respected when converting. </param>
        /// <param name="source"> The object to convert to a CornerRadius. </param>
        public override object ConvertFrom(ITypeDescriptorContext typeDescriptorContext, CultureInfo cultureInfo, object source)
        {
            if (source != null)
            {
                if (source is string) { return FromString((string)source, cultureInfo); }
                else                  { return new CornerRadius(Convert.ToDouble(source, cultureInfo)); }
            }
            throw GetConvertFromException(source);
        }
 
//Workaround for PreSharp bug - it complains about value being possibly null even though there is a check above
#pragma warning disable 56506
 
        /// <summary>
        /// ConvertTo - Attempt to convert a CornerRadius to the given type
        /// </summary>
        /// <returns>
        /// The object which was constructoed.
        /// </returns>
        /// <exception cref="ArgumentNullException">
        /// An ArgumentNullException is thrown if the example object is null.
        /// </exception>
        /// <exception cref="ArgumentException">
        /// An ArgumentException is thrown if the object is not null and is not a CornerRadius,
        /// or if the destinationType isn't one of the valid destination types.
        /// </exception>
        /// <param name="typeDescriptorContext"> The ITypeDescriptorContext for this call. </param>
        /// <param name="cultureInfo"> The CultureInfo which is respected when converting. </param>
        /// <param name="value"> The CornerRadius to convert. </param>
        /// <param name="destinationType">The type to which to convert the CornerRadius instance. </param>
        ///<SecurityNote>
        ///     Critical: calls InstanceDescriptor ctor which LinkDemands
        ///     PublicOK: can only make an InstanceDescriptor for CornerRadius, not an arbitrary class
        ///</SecurityNote> 
        [SecurityCritical]
        public override object ConvertTo(ITypeDescriptorContext typeDescriptorContext, CultureInfo cultureInfo, object value, Type destinationType)
        {
            if (null == value)
            {
                throw new ArgumentNullException("value");
            }
 
            if (null == destinationType)
            {
                throw new ArgumentNullException("destinationType");
            }
 
            if (!(value is CornerRadius))
            {
                #pragma warning suppress 6506 // value is obviously not null
                throw new ArgumentException(SR.Get(SRID.UnexpectedParameterType, value.GetType(), typeof(CornerRadius)), "value");
            }
 
            CornerRadius cr = (CornerRadius)value;
            if (destinationType == typeof(string)) { return ToString(cr, cultureInfo); }
            if (destinationType == typeof(InstanceDescriptor))
            {
                ConstructorInfo ci = typeof(CornerRadius).GetConstructor(new Type[] { typeof(double), typeof(double), typeof(double), typeof(double) });
                return new InstanceDescriptor(ci, new object[] { cr.TopLeft, cr.TopRight, cr.BottomRight, cr.BottomLeft });
            }
 
            throw new ArgumentException(SR.Get(SRID.CannotConvertType, typeof(CornerRadius), destinationType.FullName));
        }
 
//Workaround for PreSharp bug - it complains about value being possibly null even though there is a check above
#pragma warning restore 56506
 
        #endregion Public Methods
 
        //-------------------------------------------------------------------
        //
        //  Internal Methods
        //
        //-------------------------------------------------------------------
 
        #region Internal Methods
 
        static internal string ToString(CornerRadius cr, CultureInfo cultureInfo)
        {
            char listSeparator = TokenizerHelper.GetNumericListSeparator(cultureInfo);
 
            // Initial capacity [64] is an estimate based on a sum of:
            // 48 = 4x double (twelve digits is generous for the range of values likely)
            //  8 = 4x UnitType string (approx two characters)
            //  4 = 4x separator characters
            StringBuilder sb = new StringBuilder(64);
 
            sb.Append(cr.TopLeft.ToString(cultureInfo));
            sb.Append(listSeparator);
            sb.Append(cr.TopRight.ToString(cultureInfo));
            sb.Append(listSeparator);
            sb.Append(cr.BottomRight.ToString(cultureInfo));
            sb.Append(listSeparator);
            sb.Append(cr.BottomLeft.ToString(cultureInfo));
            return sb.ToString();
        }
 
        static internal CornerRadius FromString(string s, CultureInfo cultureInfo)
        {
            TokenizerHelper th = new TokenizerHelper(s, cultureInfo);
            double[] radii = new double[4];
            int i = 0;
 
            // Peel off each Length in the delimited list.
            while (th.NextToken())
            {
                if (i >= 4)
                {
                    i = 5;    // Set i to a bad value. 
                    break;
                }
 
                radii[i] = double.Parse(th.GetCurrentToken(), cultureInfo);
                i++;
            }
 
            // We have a reasonable interpreation for one value (all four edges)
            // and four values (left, top, right, bottom).
            switch (i)
            {
                case 1:
                    return (new CornerRadius(radii[0]));
 
                case 4:
                    return (new CornerRadius(radii[0], radii[1], radii[2], radii[3]));
            }
 
            throw new FormatException(SR.Get(SRID.InvalidStringCornerRadius, s));
        }
        #endregion
    }
}